


The Third Child

by ViableSourceMaterial



Category: InuYasha - A Feudal Fairy Tale, Undertale (Video Game)
Genre: And compare to my latest works, Evil Chara, Gaster Blaster Sans, Mute Frisk, Pseudoscience, See how I started off, Still, The Others Are Better, but not really, don't judge me pls, first fic, inuyasha crossover, kind of
Language: English
Status: In-Progress
Published: 2016-08-24
Updated: 2016-10-04
Packaged: 2018-08-10 20:43:26
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 1,295
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7860445
Author URL: https://archiveofourown.org/users/ViableSourceMaterial/pseuds/ViableSourceMaterial
Summary: <blockquote class="userstuff">
              <p>Ammy, a strange monster who resembles a human except for a pair of dog ears, doesn't quite know how she got here, or why she's here. Sans is here to save the day, but then a sudden truth is revealed. How will Sans take this news?</p><p>Edit 12/22/16: This fic will no longer be updated here. The full version will be posted on FanFiction, under the pen name "Amaterasu Verdana". If you would like to read the full 13 chapters, it is already complete. Under the same title.</p>
            </blockquote>





	1. Introductionism (May or May Not Be A Word)

_Writer’s Note: Hi. I’m a new writer, as you can see. This is my first fanfic, so please don’t judge me too harshly. Also, I just wanted to let you know that this fanfic will not have, and will never, have swear words or adult themes, but will have violence, pain, and LOTS of confusing plot points. Just wanted to give you a heads-up._

 

One day, Sans was sitting at his sentry post in the forest of Snowdin. He was really tired and was just about to fall back asleep when he heard sobbing somewhere behind him. He gets up and tries to find the source of the sound. He walks into a clearing and finds a woman sitting on the ground in a ball, backed against a tree. She almost looks human, except that she has dog ears, and is wearing a kimono. “Heya. What’s wrong?” Sans asks the woman. She doesn’t reply, but instead retreats further into herself. “Hey, don’t be sad. Whatever happened, it’s over. Everything is okay now.” Sans tried to comfort the woman. She muttered something inaudible. “Hey. You gonna tell me what’s wrong, or are you just gonna leave me hangin’?” “Help me. Please, help me!” She cries, louder in the second sentence. “Um, hey. What exactly do you need me to help you with?” “My friend was corrupted, and I can’t help him because I’ll be corrupted too.” She tells Sans. “Okay, then let’s take you to my house. You look cold and starving, and you might want to get some meat on those bones, yeah? I’m guessing you might wanna discuss this in a better place, too?” “Seriously?” That’s how you’re going to make a first impression? Wow. I can’t believe what’s happened to standards here.” “What? I was trying to get you to feel better. But, I guess, to each their own.” About an hour later, they were in Sans’ room. They had discussed Sans’ life. “So, that’s the gist of it, huh? The woman stated, blank-minded and staring. “Yep. So, how about you? First of all, I haven’t asked you your name this whole time. That was a screw-up on me, wasn’t it?” Sans stated, with a chuckle. The woman eventually replied, “My name is Amaterasu. But you can just call me Ammy.” “Okay, Ammy. What’s up with you? Earlier, all you told me was that-”He stated questioningly, until he was interrupted by the door opening. Papyrus walks in and says, “Sans! Have you sorted out the problem yet? I hope so, because I have finished preparing dinner. Please, come eat.” “This spaghetti is really good, Papyrus. You’ve really improved at cooking.” Sans says. “What about you, Ammy?” What do you think of it?” No response. “Ammy?”...No response. “AMMY!?” Still, no response. The next second, she’s in the bathroom, shutting the door. “Did she just… teleport?” Papyrus asks. “Yes. Yes she just did.” Sans answers, wide-eyed. They hear screaming coming from the bathroom and rush toward the door.


	2. Puns and a Lab

**Summary for the Chapter:**

> The skelebros' (nonexistent) bathroom has exploded. The gang is almost all together. And cliffhangers are my secret hobby. Mwah ha ha..

**Notes for the Chapter:**

> And we start off with the main character missing. This is clearly going to turn out well.

_ Writer’s Note: The portal mark left in this chapter, and all other chapters, is the same one found in  _ Pokemon:Mystery Dungeon: Gates to Infinity.

 

Papyrus tried to open the door, but it was forced shut by some pressure coming from the inside. Sans was about to teleport inside when a great shockwave hit them. They couldn’t see for a moment, but then the bathroom door, and the frame, were lodged in the wall across the room. Sans blinked the light out of his eyesockets only to see Papyrus staring in disbelief at the remnants of what was their bathroom. Sans followed his brother’s gaze, then gaped at what he saw. A charred mark left in the floor, with a filament of smoke trailing up from the mark. The mark itself was similar to a black hole. “What the…” managed Papyrus, still gaping. “S-Sans, w-what is that?” managed Papyrus, still in shock. 

 

“I don’t know, Papyrus. Guess you could say it’s a mist-ery.” 

 

“OH MY GOD SANS!” shouts Papyrus.

 

“Anyways, let’s see what this is…” Sans says, curiously.

 

Some time later, Sans and Papyrus call Alphys and now she and Undyne are there, and everyone is looking at the mark. Sans leaves. “W-where did he go, Papyrus?” Alphys asks.

 

“He probably just went to his secret back room.” Papyrus answers.

 

“Where is it?” asks Undyne.

 

“Around the back.” Papyrus answers again.

 

They all head out and to the door. Alphys tries to open it, but the door is locked. Sans calls from inside, “Who’s there?”

 

“I-It’s just us, Sans. C-Can we come in?” Alphys stutters.

 

“Sure, but only Alphys.” Sans replies. A click is heard from the door. “Come on in.” she hurries in and shuts the door behind her.

 

“Let’s go before those losers want us to listen to their babble. It’s probably not important anyway. “ Undyne says. They all walk back to the house.

 

“So, the mark is similar to a black hole, right?” Alphys says.

 

“Yeah. Hang on, let me get out some of Gaster’s notes.” Sans replies.

 

“Y-You have Gaster’s notes!?!?” Alphys stutters, shocked.

 

“Well yeah, I was his son, not to mention his colleague. _~~Do you not remember our time together in the lab, Alphys?~~  _We worked on... things together.” Sans says, then shakes his head as if ridding himself of the thought.

 

“Well, I won’t ask into it, it seems to be a sore subject, but, did you work on anything like this?” Alphys says, sounding curious.

 

“Yeah” Sans says, “although not exactly. It could be void magic, or maybe a form of interdimensional travel.”

 

“Looks to be the latter.” Alphys responds.

 

_ Author’s Note: For those of you who don’t know, this fanfic was rated “Teen” for violence ONLY. There will not, and never will, be major swearing or adult themes. I may use the word crap occasionally, but this is a mainly kid-friendly story. Remember, the rating system is your friend. If you don’t want to read about people dying, or Undertale characters duetting opera with Inuyasha characters in falsetto, DON’T READ THIS! (I know it’s a little bit late for that, just needed to get the feels out, ya know?) _


	3. Yay Explosions

**Summary for the Chapter:**

> Sans and Alphys are doing... something. We then cut over to Ammy in the void, giving us a plot point that I really don't use again.

**Notes for the Chapter:**

> I put all my stuff in Google Docs bc I'm used to the FF document-uploading thing. This means I have to copy-paste whole chapters at a time. When I get to Chapter 9, you'll see why I don't like this.

“Okay then. Let’s begin. We know that it was caused by magic,” Sans says, “So, that means we can narrow our choices down to either void magic or dimensional teleportation.”

“W-Well, judging by the mark left, it could use portal gateways.” she added.

“Good, good. Next, why would she leave like this?” Sans replied.

“Maybe she was suffering. You know, like that AU, BOTWOT, except different?”

“Hmm. That’s good info, but it may be just a theory. Hopefully we can solve this.”

“I think that m-maybe we could just, um, you know, take some s-samples?”

“Good idea.”

Later, they were back in the lab. Sans was investigating the samples they took.”The marks were made with a gateway. Hmm… Interesting. The gateway was composed of LOVE and Photoignesium.”

“LOVE? Okay, seems somewhat normal but… what exactly is photoignesium?”

“Photoignesium is an element I recently discovered. It’s basically void fire.”

“W-Wait. You said that you, um.. D-discovered it, right?”

“Yeah.”

“Then, w-wouldn’t that mean maybe she created it?”

“Yeah, you’re right.”

Meanwhile…

“Whew. Glad I got out of that one. The timelines..”

“Ammy.”

“Yeah, Gaster?”

“Why did you use the void gateway?”

“I wanted them to have an idea of what I'm doing.”

“Oh."

“Anyways, I wanted to show you the new thing I found with Photoignesium.”

“You mean you found a way to combine Photoignesium with other elements?”

“Yes. I’ve combined it with light. Only light. Wanna see?”

“Sure.”

Mean-meanwhile…

“This is puzzling. They're still working, and it is almost time for dinner!” Papyrus said, worriedly.

“Well, let’s go check on them.” she replied.

An explosion. Screaming.


End file.
